CAMERA SYSTEM FOR A MOTOR VEHICLE, MIRROR REPLACEMENT SYSTEM WITH SUCH A CAMERA SYSTEM AND DRIVING ASSISTANCE SYSTEM WITH SUCH A SYSTEM

Description

AREA OF INVENTION

[0001] The invention relates to a camera system for a motor vehicle, in particular a commercial vehicle. Furthermore, the invention relates to a mirror replacement system for a motor vehicle that includes such a camera system, and to a driver assistance system for a motor vehicle that includes such a camera system. STATE OF THE ART

[0002] Camera systems are increasingly being used on or in vehicles, for example, as a supplementary system for conventional mirrors, such as to provide parking assistance to car drivers. Furthermore, camera systems are increasingly being used in so-called mirror replacement systems, in which mirrors required for motor vehicles, such as exterior mirrors (main mirrors), interior mirrors on cars, or wide-angle and front mirrors on commercial vehicles, are completely replaced.With such mirror replacement systems, the corresponding field of vision, which is conventionally visible through a mirror, is displayed to the driver continuously and in real time on a monitor or other display unit, for example, inside the vehicle. This allows the driver to view the corresponding field of vision at any time, even though no mirror is present. Furthermore, camera systems are used in vehicles as part of so-called Advanced Driver Assistance Systems (ADAS). In these systems, either the data recorded by the camera systems is displayed to the driver, depending on the current driving situation, or the captured image data is analyzed to control other vehicle components, such as distance and / or obstacle detection, road condition detection, lane keeping assist, traffic sign recognition, etc.

[0003] For use on vehicles, legal regulations or the specific requirements or intended use of the camera system often impose certain demands on the recording device (e.g., camera). These requirements may relate to resolution, the angular range the camera system must cover, sharpness in terms of image depth, and similar factors. These requirements, for example, to extract the desired data from the recorded image data, are sometimes conflicting. For instance, a wide angular range may need to be captured simultaneously, while at least one part of the captured angular range requires very high resolution and depth of field. Therefore, it is generally necessary to provide multiple recording units for a more complex camera system on a vehicle, even if these units are identical or different.Overlapping areas around the vehicle are targeted, and the image data captured by the multiple recording units is then combined, for example, into a single image. Alternatively, by using multiple recording units, each unit can be assigned its own task with regard to the various, potentially conflicting requirements. These tasks can then be analyzed using the image data captured by the multiple recording units in such a way that the information assigned to and to be extracted from each image, for example, for a driver assistance system, is extracted from it.

[0004] In practice, this means that, for example, in a mirror replacement system, each field of view must typically be captured by separate imaging units, i.e., at least one imaging unit per field of view. In the prior art, particularly in the automotive sector, camera systems are used for this purpose, employing multiple separate image sensors and optics, i.e., separate imaging units, whose image data is subsequently stitched together. Alternatively, it is also known to use a single optic with multiple image sensors, which are then combined to form a larger image sensor area, thus enabling the capture of a larger image with a single optic but separate (multiple) image sensors.

[0005] From JP 2006343545 and JP 2009058648, camera systems for a passenger car are known that capture an area in the front or rear of the vehicle. These camera systems are provided in addition to the conventional vehicle mirrors. The camera systems each have lens arrangements with a special distortion curve that has an inflection point within the imaged area on the image sensor.

[0006] From EP 2 881 927 A1, a warning device for a passenger car and an exterior mirror device for a vehicle are known. This includes an image capture unit on the side exterior mirror, which captures the area around the passenger car.

[0007] From DE 10 2010 032 411 A1, a device for monitoring the lateral and rear surroundings of a commercial vehicle is known. For this purpose, additional cameras are attached to the exterior mirrors of the towing vehicle, which have a relatively small detection range, in particular below or up to 90°.

[0008] Patent EP 2 623 374 B1 discloses a mirror replacement system for a commercial vehicle for displaying legally prescribed fields of view of a main mirror and a wide-angle mirror on the same side of the vehicle on a display unit in the driver's cab of the commercial vehicle. According to EP 2 623 374 B1, the displayed image is modified so that the image stretching in the wide-angle direction is reduced. TASK OF INVENTION

[0009] Based on this, the object of the invention is to provide a mirror replacement system with a camera system for a vehicle, in which even complex requirements regarding the quality and range of the image data can be met as flexibly as possible with a single recording unit containing a single image sensor with a single sensor area and a single optical element, and which offers improved display quality for the driver. Furthermore, it is an object to provide a driver assistance system that can meet complex image acquisition requirements for the driver assistance system with minimal effort using a camera system. PRESENTATION OF THE INVENTION

[0010] This problem is solved by a mirror replacement system having the features of claim 1 and by a driver assistance system having the features of claim 14. Preferred embodiments are specified in the dependent claims.

[0011] In the present description, a camera system with a recording unit comprising an optical element and an image sensor with an image sensor area is understood to mean a camera system that has at least one recording unit. Further recording units may be provided within the camera system, which either also fulfill the requirements of claim 1 for the camera system or are configured differently, for example, to capture fields of view located to the left or right of the vehicle. It is essential that the recording unit of the camera system defined in claim 1 comprises exactly one optical element and exactly one image sensor with an image sensor area and is further adapted as defined in claim 1.

[0012] The camera system used for the mirror replacement system is based on the idea of ​​adapting the optical element of the recording unit (e.g., camera) in such a way that a single image sensor can capture both a high-resolution area and a relatively wide angle (wide-angle) image, and both can be simultaneously projected onto the same sensor. An image sensor is understood to be an essentially flat recording surface, with the area of ​​the sensor on which the image captured by the optical element is actually projected being called the image sensor area. The image sensor area, as well as the image sensor itself, is rectangular, meaning the image sensor area is a rectangular surface with a boundary and boundary points at each pair of parallel edges.The image sensor is also usually rectangular and essentially corresponds to the shape of the image sensor surface.

[0013] The optical element, for example, consists of an arrangement of several lenses connected in series and possibly other optical components. Its purpose is to direct, focus, etc., an incident light beam onto the image sensor or image sensor surface. The selection of lenses and optical components determines the properties of the optical element, particularly its distortion. The optical element has an optical axis, which, in the case of a rotationally symmetric system, is the rotational symmetry axis of the system. In both rotationally symmetric and non-rotationally symmetric systems, it is ensured along the optical axis that the resulting image is accurately reproduced.The passage of the incident light ray through the optical element is distortion-free, while distortion occurs with increasing distance from the optical axis. This distortion is a geometric aberration that leads to a local change in the image scale. Often, this change in scale is a change in magnification with increasing distance of the image point from the optical axis and, in a rotationally symmetric system, rotationally symmetric around a point, the so-called center of distortion, which corresponds to the intersection of the optical axis with the image sensor surface. Depending on the optical system, the distortion can vary; for example, with pincushion distortion, the magnification increases towards the edges of the image field, while with barrel distortion, it decreases towards the edges.

[0014] Furthermore, the optical axis is the axis along which an incident light ray usually passes through the optical element without deflection and hits the image sensor surface.

[0015] The camera system used for the mirror replacement system in a motor vehicle is based on the idea of ​​actively shaping the distortion of the optical element by using and selecting special lens arrangements as the optical element itself. This allows for the simultaneous achievement of seemingly contradictory requirements, such as wide-angle imaging (i.e., imaging with a large field of view) and essentially distortion-free or low-distortion imaging with high resolution for the desired image areas. To this end, the optical element exhibits distortion with a distortion curve r = f(α), where r is the distance of an object point imaged on the image sensor surface to the intersection of the optical axis with the image sensor surface, and α is the angle between the optical axis of the optical element and the ray incident on the optical element from the object point.The distortion curve r = f(α) has an inflection point (αw; rw), preferably exactly one inflection point (αw; rw) within 0 < r(α) < rmax, where rmax is the distance r = f(αmax) on the image sensor surface from the optical axis to the edge point of the image sensor surface furthest from it. The object point is a point from which an incident light ray originates, which is imaged onto the image sensor surface by means of the incident light ray passing through the optical element. The angle α between the optical axis of the optical element and the ray incident from the object point into the optical element corresponds to the minimum required lens aperture angle for the corresponding object point and is subsequently referred to as the object angle α.In other words, the object angle α is the angle between the optical axis and the light ray incident on the optical system from the object point, as long as the ray remains outside the optical system or optical element. The angle (90° - α) is therefore the angle between the incident light ray at the point where it enters the optical element and a surface passing through this point and perpendicular to the optical axis.

[0016] Thus, the object angle α denotes the angle formed by a light ray entering the optical element from an object point located outside the optical element and the optical axis. This object point is then imaged onto the image sensor surface after passing through the optical element.

[0017] The distortion curve r = f(α) of the optical element thus has an inflection point within the image sensor area, for which the second derivative of the distortion curve r = f(α), i.e., r'' = f''(α) = 0. Simultaneously, in an α,r coordinate system, in the region between the origin of the distortion curve and the edge point of the image sensor area furthest from the origin, the distortion curve exhibits a left-curved region on one side of the inflection point and a right-curved region on the other side of the inflection point, where a right-curved region (r'' = f''(α) < 0) exists in the region 0° < α < αw and a left-curved region (r'' = f''(α) > 0) exists in the region αw < α < αmax, where αmax is defined by the boundary of the image sensor area.αmax is the angle α that corresponds to the maximum distance rmax from the optical axis to the edge point of the image sensor area furthest from it. For example, if the optical axis lies centrally on the image sensor area, i.e., at the centroid of a substantially rectangular image sensor, then rmax corresponds to the distance from the optical axis on the image sensor area to any vertex of the rectangle. If the optical axis is off-center, i.e., not at the centroid of the image sensor area, then rmax is defined by the distance from the optical axis to the corner of the rectangle furthest from the optical axis in the case of a substantially rectangular image sensor. The origin of the α,r coordinate system corresponds to the optical axis on the image sensor area.

[0018] By using the described distortion curve r = f(α), a specific or defined, relatively large, distortion-free or essentially distortion-free area near the intersection of the optical axis with the image sensor, or the optical axis on the image sensor, can be imaged with high resolution. Simultaneously, a large angular range can be captured, allowing for relatively high resolution for larger α values, i.e., object points located further from the optical axis. This resolution is still sufficient, for example, for representing legally required fields of view. This approach avoids the need for an extremely high-resolution image acquisition unit that would generate large amounts of data.Post-processing of the image data for distortion correction, which would not affect the existing resolution anyway, especially not increase it, is therefore not necessary or less necessary.

[0019] In particular, the distortion curve, which has the form of an S-curve, allows a single image sensor with a relatively low resolution to still produce an image that meets the requirements for sharpness, resolution, and similar aspects, as well as the image area. For example, this enables the imaging of two fields of view around a commercial vehicle by a single camera unit and its display on a monitor or display unit within a mirror replacement system, even if one of the fields of view corresponds to the field of view of a wide-angle mirror. Because a relatively low-resolution image sensor or camera unit can be used, the system can be designed more cost-effectively and simplified. This is because a smaller amount of data needs to be processed in the processing unit that handles the data from the camera unit, thus reducing the number of data-processing components, such as...The computing unit or the working memory of the processing unit can be designed to be smaller and therefore more cost-effective. Furthermore, with similar designs of the processing units, the processing speed is higher, or the system load is lower, so that on the one hand, faster data processing is possible, and on the other hand, the processing unit, especially the underlying electronic system, runs cooler, thus enabling easier thermal management.

[0020] Besides the fact that a single, shared recording unit can, for example, capture data from two fields of view, it is not necessary to merge data from separate recording units, at least to the extent that the single, shared recording unit captures the desired sub-area of ​​the vehicle's surroundings. Furthermore, it is simpler to integrate and position the fewer required recording units on the vehicle.

[0021] Simultaneously, the distortion curve allows for very high resolution precisely where it is needed or required, i.e., in the most relevant area of ​​the vehicle's surroundings that lies within the captured sub-area. Finally, it is possible to utilize the entire image sensor area to achieve sufficiently high resolutions across the entire sensor surface. This allows, for example, an area of ​​the image sensor read out by a data processing unit to be shifted (panned) as needed. Such panning of the read-out area can be performed, for instance, depending on the driving situation, or if the driver desires manual adjustment of the area captured by the recording unit and, if applicable, displayed on a playback unit in the vehicle.This means that it is not necessary to provide mechanical tracking of the recording unit to follow the viewed area. Instead, this can be achieved by digitally "shifting" the read-out area on the image sensor surface, making the camera system more cost-effective and robust with a lower probability of failure.

[0022] For a rotationally symmetric optical element, the distortion curve r = f(α) is also rotationally symmetric, meaning it is identical for all angles β around the optical axis, which is imaged as a point on the image sensor. For a non-rotationally symmetric optical element, it is possible to provide different distortion curves r = f(α) for different partial angular ranges around the optical axis imaged on the image sensor, i.e., rβ1 = fβ1(α), rβ2 = fβ2(α) ... rβn = fβn(α), which apply to specific partial angular ranges around the optical axis on the image sensor. In principle, the partial angular ranges for which a common distortion curve applies can be arbitrarily large, as long as the arrangement of lenses and other optical components around the optical element allows for this.

[0023] Preferably, the distortion curve r = f(α) of the camera system has exactly one inflection point (α w ; rw ) within 0 < r(α) < r max. This makes it possible to optimally utilize the available image sensor area with regard to the requirements placed on camera systems in vehicles, in particular with regard to resolution and accuracy on the one hand and the angular range of the angle captured by the camera system on the other.

[0024] According to a particularly preferred embodiment, the slope r' = dr / dα of the distortion curve r = f(α) is maximal in the region 0 < α < αw at the origin or zero point (r = f(0) = 0) of the distortion curve. This means that in the immediate vicinity of the optical axis on the image sensor surface, the slope of the distortion curve r = f(α) is maximal and then decreases further towards the inflection point. The distortion curve need not have an absolute maximum at the zero point, although this is not excluded. Rather, it is usually sufficient if, in the depicted region of the distortion curve r = f(α), it exhibits a maximum at the zero point with respect to the region 0° < α < αw. This allows a relatively large area around the optical axis, or extending from the optical axis within this region, to be rendered with maximum distortion.The distortion curve can be represented with a relatively large slope, especially in comparison to conventional distortion curves, such as an equidistant distortion curve. In the latter case, the distance r for equal angles α is smaller on the image sensor area than in the distortion curve, which has the largest possible slope in the region of the zero point or directly at the zero point α = 0, r = 0.

[0025] According to a further particularly preferred embodiment, the slope r' = dr / dα for the distortion curve r = f(α) is minimal at the inflection point (αw; rw). Similar to the consideration of maximizing the slope at the zero point of the distortion curve, the minimum here is only a relative minimum for the depicted region of the distortion curve on the image sensor and not necessarily an absolute minimum over the entire (virtual and possibly external) distortion curve. Rather, it suffices if the minimum is a minimum within the depicted region or within the region of the image sensor area, i.e., a minimum in the region 0° < α < αmax.

[0026] It is also preferred that the slope r' = dr / dα of the distortion curve r = f(α) is maximal in the range 0° < α < αmax for αmax, i.e., at the maximum radius rmax. This maximum need not be an absolute maximum of the distortion curve. Rather, it is sufficient if the maximum of the distortion curve for the range αw < α < αmax lies at this location.

[0027] The distortion curve, which has the aforementioned properties, can, for example, according to a preferred embodiment, be described by a polynomial function. f α = ∑ i = 0 n α i α i Alternatively, the distortion curve r = f(α) can also be represented by a spline of degree n, a polynomial sequence. That is, it can be defined as a function piecewise composed of polynomials of degree n or lower. In this case, the distortion curve is thus defined not by a single polynomial, but by several piecewise polynomials. Another possibility is to define a Bézier curve, which is a parametrically modeled curve and can therefore also provide the requirement for (exactly) one inflection point within the range 0 < r < r max. These mathematical functions enable a relatively simple modeling of the optical element, or rather, of the distortion curve of the optical element.

[0028] In a particularly preferred embodiment, the centroid of the mostly rectangular image sensor area and the intersection of the optical axis with the image sensor area, or the mapping of the optical axis onto the image sensor area, are offset from each other. In particular, the optical axis is eccentric with respect to the image sensor area, i.e., it is not located at the centroid. This makes it possible to define and model more precisely and effectively desired areas with regard to distortion on the image sensor area and to cut out or extract them as needed by a processing unit, for example, to display them to the driver of the vehicle on a display unit or to evaluate them with regard to specific data. Thus, the area of ​​interest can be selected across almost the entire surface of the image sensor and cut out or extracted by the data processing unit.The data is read out and further processed.

[0029] Preferably, the optical element is implemented by a plurality of lenses connected in series, optionally supplemented by further optical components, such as filters. For example, the optical element contains at least one lens with a non-partially spherical surface, at least one aspherical lens, and / or at least one lens with a freeform surface. It is particularly preferred to combine at least two lenses that differ from each other in their properties and shapes, since this allows for the provision of an optical element that has (exactly) one inflection point (αw; rw) in its distortion curve r = f(α). If a series of rotationally symmetric lenses with different surfaces are connected in series, a distortion curve r = f(α) is obtained that is identical for every rotation angle β about the optical axis.In this case, the optical element is therefore rotationally symmetrical about its optical axis. This is particularly advantageous if the recording area also has a substantially rotationally symmetrical requirement, for example with regard to resolution.

[0030] Alternatively, it is also possible to provide an optical element that exhibits a distortion not rotationally symmetric about its optical axis, such that a first distortion curve rβ1 = f(α) for a rotation angle β1 about the optical axis differs from a second distortion curve rβ2 = f(α) for a rotation angle β2 about the optical axis. Preferably, however, the distortion curves are identical or very similar, at least in certain regions, i.e., for specific angular ranges about the optical axis, so that the requirements for resolution, angular range, and similar properties of specific areas of the captured image can be met. In principle, any number of distortion curves rβn = f(α) can be provided. For non-rotationally symmetric distortion, however, it is sufficient that at least partial regions are provided with a first distortion curve rβ1 = f(α) and a second distortion curve rβ2 = f(α).If non-rotationally symmetric distortion is desired, it is preferable for the optical element to be anamorphic, i.e., not rotationally symmetric, so that different distortion curves exist depending on the rotation angle around the optical axis. For example, one or more of the lenses forming the optical element could be anamorphic. Alternatively, an arrangement of individual lenses or optical components of the optical element that is at least partially eccentric with respect to the optical axis could be chosen.

[0031] Furthermore, the camera system preferably includes at least one processing unit for processing the data from the recording unit and / or a playback unit for displaying information captured by the recording unit in a way that is perceptible to the driver of the vehicle. The processing unit for processing the data can, for example, be integrated into the vehicle's general on-board computer (ECU), or it can be a separate unit specifically designed for the camera system, or it can be integrated into the camera system itself. The playback unit can be configured, for example, as a monitor, multiple monitors, a projection onto other components of the vehicle, or similar. In addition to a visual playback unit, the playback unit can also be designed as an audio playback unit, for example, additionally or supplementarily.Furthermore, it can be a playback unit that warns the driver only in certain driving situations, for example as part of a driver assistance system, which in turn can be implemented by a visual display, an acoustic display or a haptic display, such as a vibration of the steering wheel, if an evaluation of the image data captured by the camera system by the processing unit sends a corresponding message to the playback unit.

[0032] According to the invention, the camera system is used as part of a mirror replacement system. Mirror replacement systems for vehicles are increasingly used, replacing conventional mirrors on or in the vehicle. Which mirrors are mandatory on a vehicle and can or should therefore be replaced as part of a mirror replacement system is generally stipulated by legal regulations, in Europe, for example, by Regulation No. 46 of the United Nations Economic Commission for Europe (UNECE) (Addendum 45, Revision 6, currently available). These are to be distinguished from so-called supplementary vision systems, which are non-mandatory visual aids and make visible an area that is not intended for the driver's continuous and uninterrupted viewing according to a legal regulation. An example of such a supplementary vision system is, for instance, a reversing camera on a vehicle as part of a parking assistance system.

[0033] In many countries around the world, passenger cars are required to have an interior rearview mirror (according to ECE-R46 "Interior Mirror Group I") and a (small) main rearview mirror (according to ECE-R46 "Main Rearview Mirror (Small) Group III") on the driver's side and often also on the passenger's side. For commercial vehicles, an interior rearview mirror is generally not required, as the driver's cab obstructs the view to the rear. Instead, a main rearview mirror (large) (according to ECE-R46 "Main Rearview Mirror (Large) Group II") and a wide-angle mirror (according to ECE-R46 "Wide-Angle Mirror Group IV") are usually required, along with other mirrors. Main rearview mirrors are those mounted on the outside of the vehicle and visible to the driver as exterior mirrors.Depending on national regulations, additional mirrors may be required on commercial vehicles, such as a close-range / approach mirror (according to ECE-R46 "Close-range / approach mirror group V") and / or a front mirror (according to ECE-R46 "Front mirror group VI").

[0034] The areas around the vehicle that must be visible to the driver using the various mirrors, and therefore also via a camera-monitor system, are stipulated in the relevant legal regulations of individual countries or regions. Generally, a so-called field of vision is defined, which refers to a flat and horizontal portion of the roadway around the vehicle and which must be continuously visible to the driver at all times and in real time.

[0035] For example, the field of vision of a passenger car's interior mirror is defined in ECE-R46 such that the driver can see a flat and horizontal portion of the roadway, centered on the vehicle's longitudinal median plane, 20 m wide, and extending from the horizon to 60 m behind the driver's eye points. A field of vision for a main exterior rearview mirror of a passenger car is defined, with respect to the driver's side of the vehicle, such that the driver can see at least a flat and horizontal portion of the roadway 5 m wide, bounded on the vehicle side by a plane parallel to the vehicle's vertical longitudinal median plane, passing through the outermost point on the driver's side of the vehicle, and extending from the horizon to 30 m behind the driver's eye points.Furthermore, the field of view of the main exterior rearview mirror includes a 1 m wide strip of the roadway, which is bounded on the vehicle side by a plane parallel to the vertical longitudinal median plane of the vehicle, passing through the outermost point on the driver's side of the vehicle, and which begins 4 m behind the vertical plane passing through the driver's eye points. The field of view of an exterior rearview mirror on the passenger side is defined accordingly on the passenger side of the vehicle.

[0036] The field of vision of a main mirror (main exterior rearview mirror) on the driver's side (the same applies to the passenger side) of a commercial vehicle is defined, for example, in ECE-R46, as follows: the driver must be able to see at least a flat and horizontal section of the roadway 4 m wide, bounded on the vehicle side by a plane parallel to the vertical longitudinal median plane of the vehicle and passing through the outermost point on the driver's side of the vehicle, and extending from the horizon to 20 m behind the driver's eye points. Furthermore, this field of vision includes a 1 m wide strip of the roadway, bounded on the vehicle side by a plane parallel to the vertical longitudinal median plane of the vehicle and passing through the outermost point on the driver's side of the vehicle, and beginning 4 m behind the vertical plane passing through the driver's eye points.The field of view of a wide-angle mirror, which is generally only fitted to commercial vehicles and not passenger cars, is defined such that the driver can see at least a flat and horizontal section of the roadway 15 m wide, bounded on the vehicle side by a plane parallel to the vertical longitudinal median plane of the vehicle and passing through the outermost point on the driver's side of the vehicle, and extending at least 10 m to 25 m behind the driver's eye points. Furthermore, this field of view of this wide-angle mirror includes a 4.5 m wide strip of the roadway, bounded on the vehicle side by a plane parallel to the vertical longitudinal median plane of the vehicle and passing through the outermost point on the driver's side of the vehicle, and beginning 1.5 m behind the vertical plane passing through the driver's eye points.

[0037] According to ECE-R46, the field of vision of a close-range or approach mirror is, for example, such that the driver can see at least a flat and horizontal part of the roadway on the outside of the vehicle, bounded by: a plane parallel to the vertical longitudinal median plane of the vehicle and passing through the outermost point on the passenger side of the vehicle; a plane parallel to this plane and 2 m away from it; a plane 1.75 m behind the vertical plane passing through the driver's eye points and parallel to it; a vertical plane 1 m in front of the vertical plane passing through the driver's eye points and parallel to it; or a plane passing through the outermost point of the vehicle's bumper, if this plane is less than 1 m in front of the vertical plane passing through the driver's eye points and parallel to it.For vehicles where the field of vision of a close-range or approach mirror is captured by a mirror mounted more than 2.4 m above the ground, or by a corresponding receiving device, the described field of vision is extended such that the driver can see a flat, horizontal area of ​​the road along the side of the vehicle and outside the field of vision of a close-range or approach mirror defined above, which may be rounded at the front with a radius of 2 m and is bounded by the following lines: in the transverse direction of the vehicle, the plane that runs 4.5 m in front of the side plane of the vehicle; to the rear, the plane that is parallel to a vertical plane that passes through the driver's eye points and is located 1.75 m behind this plane; to the front, the plane that is parallel to the vertical plane that passes through the driver's eye points and is located 3 m in front of this plane.

[0038] According to ECE-R46, the field of vision of a front mirror is such that the driver can see a flat and horizontal part of the roadway, bounded by the following planes: a vertical transverse plane passing through the foremost point at the front of the vehicle; a vertical transverse plane 2 m in front of this plane; a plane parallel to the vertical longitudinal median plane of the vehicle, passing through the outermost point on the driver's side of the vehicle; and a plane parallel to the vertical longitudinal median plane of the vehicle, passing 2 m from the outermost point on the passenger's side of the vehicle.

[0039] Where this description refers to fields of view of a primary mirror, a wide-angle mirror, an internal mirror, a close-range mirror, a front mirror, etc., this refers to the corresponding fields of view as defined in the respective national regulations and corresponding to the described fields of view of the mirrors. If no corresponding national regulations or definitions for fields of view exist, the dimensions as described shall be considered the definition for the respective field of view.

[0040] Preferably, the mirror replacement system, which, in addition to a processing unit for the data captured by the camera system, preferably includes a playback unit for displaying information captured by the recording unit in a way that is perceptible to the driver of the vehicle, is designed such that the playback unit presents the data in a way that is visible to the driver of the vehicle. This can be done, for example, by means of monitors inside or outside the vehicle, or by projection onto components of the vehicle.

[0041] The mirror replacement system is adapted to display at least one field of view for the driver of the vehicle on the display unit, namely the field of view of a main mirror and the field of view of a wide-angle mirror on the same side of the vehicle, which are captured by the common recording unit of the camera system with a common image sensor, i.e. a single image sensor, and displayed for the driver of the vehicle on the display unit.In particular, the characteristic distortion curve of the optical element of the recording unit, which is a common, single recording unit for the field of view of the main mirror and the field of view of the wide-angle mirror, makes it possible to provide both the relatively large angle to be represented, which is required for a field of view of a wide-angle mirror of a commercial vehicle, and sufficient resolution, especially with regard to the field of view of the main mirror and further with regard to the depth, i.e. the extension of the field of view of the main mirror along the rear of the commercial vehicle.

[0042] In a preferred embodiment, where at least two fields of view around the vehicle are displayed for the driver to see and are captured by the same recording unit, i.e., the same optical element and the same image sensor, a first field of view is displayed in a first area of ​​the display unit, and a second field of view is displayed in a second area of ​​the display unit that is optically separated from the first area. For example, the optical separation can be achieved by displaying the first field of view and the second field of view in two separate areas on a common monitor, i.e., a common display unit, using a split-screen method.For example, if the field of view of a primary mirror and a wide-angle mirror is captured, the field of view of the primary mirror can be displayed in a first area, and the field of view of the wide-angle mirror in a second area located above or below it. Preferably, a fixed separation, such as a bar or a superimposed optical separation like a line, is provided between the two displays. This means the processing unit extracts from the captured image data those elements to be displayed in the first area and those to be displayed in the second area. This makes it easy for the driver to see which field of view is displayed where. The display of the fields of view in a first or second area on the display unit preferably remains unchanged during vehicle operation with regard to where each field of view is shown.

[0043] It is preferred that the processing unit be adapted to separate the data received from the recording unit into those to be displayed in the first area of ​​the playback unit and those to be displayed in the second area. Further image processing by the processing unit can, of course, be carried out, so that, for example, additional information is displayed, hazards are indicated, or, while ensuring that the entire field of view is always visible, it is enlarged or reduced within the designated area, e.g., depending on the direction of travel and / or speed.

[0044] It is possible that the data for the first area and the data for the second area are extracted from overlapping areas on the image sensor; that is, the area on the image sensor from which the information for the first area is extracted and the area on the image sensor from which the information for the second area is extracted overlap with each other, for example, in the horizontal direction. After the information has been extracted from the image sensor, the extracted areas can be digitally enlarged, possibly with different scaling factors.

[0045] Instead of displaying the image in two separate areas on the display unit, two fields of view can also be shown in a single, seamlessly adjacent display (panoramic view). This is possible because the data to be displayed is captured using a common image sensor, and thus the same optics are used to capture both fields of view. This eliminates the need to combine two different optics with different distortions into a seamless image, which would require considerable post-processing adjustments and computational effort. Nevertheless, the two areas can be enlarged or reduced with different scaling factors, at least in the direction perpendicular to their (virtual) point of proximity. For example, they can be scaled the same vertically but differently horizontally.

[0046] Preferably, the processing unit is adapted to adjust the information extracted from the data recorded by the recording unit for the first and / or second area with respect to its position in the image captured by the recording unit on the image sensor, depending on information acquired by a sensor and transmitted to the processing unit, such as the vehicle's direction of travel. For example, if the field of view of a wide-angle mirror and a main mirror of a commercial vehicle are acquired by the recording unit, a direction sensor, such as a sensor that detects the steering angle, can provide data that causes the processing unit to adjust the area from which the information is extracted and displayed to the driver on the display unit.For example, when driving straight ahead, the information to be displayed for the field of view of the main mirror can be located in a first area on the image sensor surface, while when driving around a curve, such as during a turn, this information can be located in a second area on the image sensor surface. Accordingly, the desired, visible area is tracked without actually tilting the camera unit. The distortion curve with its inflection point in the area of ​​the image sensor surface ensures that the best possible and sufficient image sharpness is maintained even if the extracted area on the image sensor shifts.In particular, the area of ​​the image sensor surface that is read out is shifted (so-called panning) to provide the driver with the best possible view of the field of vision. Due to the distortion curve of the camera unit, this shift can also be achieved without significant distortion correction or image processing. Mechanical tracking of the camera unit is therefore no longer necessary.

[0047] This can also be used if the driver of the vehicle wants to manually adjust the virtual mirror created by the camera-monitor system to match a real mirror.

[0048] Depending on requirements, a single vehicle sensor can be used as the sensor, or a combination of at least two vehicle sensors can be used, for example functionally identical sensors from different sides of the vehicle (e.g. wheel sensors) or different types of sensors.

[0049] A sensor other than one that indicates the vehicle's direction of travel can also trigger the shift of the extracted information area on the image sensor surface.

[0050] According to the invention, in the mirror replacement system, the optical axis of the receiving unit, in particular the optical element of the receiving unit, is arranged such that it intersects one of the fields of view. The optical axis intersects the field of view on a flat, horizontal part of the roadway at an intersection point at a maximum distance of 5 m from a lateral boundary line of the vehicle, wherein the lateral boundary line is a line of intersection of a plane parallel to the longitudinal median plane of the vehicle, which passes through the outermost point of the vehicle. This makes it possible for a line of sight passing through this intersection point, and which is limited by the boundary of the field of view of the main mirror, to lie in that region of the distortion curve which exhibits a rightward curvature, that is, in that region for which the second derivative of the distortion curve is less than 0 (r" = f "(α) < 0).The inflection point of the distortion curve is advantageously located outside this viewing distance. This allows this area to occupy a relatively large area on the image sensor for a given angle α of the incident light beam, compared to conventional distortion curves, and thus be displayed with high resolution.

[0051] According to a preferred embodiment, the mirror replacement system is adapted to capture a portion of the vehicle using the recording unit and display it on the playback unit for the driver to see. This allows the driver to easily orient themselves and, particularly in the case of commercial vehicles, provides a good overview of the vehicle's position and any obstacles.

[0052] As an alternative or supplement to a mirror replacement system, the camera system can be used for an Advanced Driver Assistance System (ADAS). In this case, it is possible to evaluate the captured information, for example, with regard to other vehicle environment information, such as the presence of lane markings, traffic signs, other road users, and the like. This information can then be fed to adaptive cruise control (ACC), emergency braking (EBC), active lane keeping assist (LKA), lane change assist, or similar systems that are part of or constitute the ADAS, and a control unit can be used to send corresponding outputs to other vehicle components.

[0053] In a particularly preferred embodiment, the camera system is directed forward when viewed from the vehicle's forward direction of travel. This is especially advantageous for automatic distance control or similar systems. The information acquired by a driver assistance system can also be output and / or displayed to the driver, either as part of a mirror replacement system or another assistance system. For example, it is possible to provide the driver with appropriate warnings via audio signals, haptic signals, or similar means, such as a vibration of the steering wheel, thus warning them of a potentially dangerous situation. BRIEF DESCRIPTION OF THE FIGURES

[0054] The invention is described below purely by way of example with reference to the attached figures, wherein Figure 1a schematic view of a mirror replacement system that uses a camera system according to the invention; Figure 2 a perspective view of a commercial vehicle with a camera system according to the invention; Figure 3 a simplified sectional view of the essential components of the camera system; Figure 4 a perspective view accordingly Figure 3 the essential components of the camera system; Figure 5 An embodiment of the structure of the optical element of the recording unit of the camera system is schematically illustrated in a cutaway perspective view; Figure 6 another embodiment of the detailed structure of the optical element of the camera system's recording unit in a cutaway perspective view; Figure 7 The distortion curve of the optical element of the camera system's recording unit is shown in an α,r coordinate system; Figure 8the first derivative of the distortion curve of the optical element of the recording unit of the camera system shows; Figure 9 the second derivative of the distortion curve of the optical element of the recording unit of the camera system shows; Figure 10a shows the distortion curve of the optical element of the camera system's recording unit compared to conventional distortion curves; Figure 10b a detail from Figure 10a is that shows the distortion curves around the origin of the distortion curve; Figure 11 a schematic view of the image sensor of the recording unit, showing the fields of view of a primary mirror and a wide-angle mirror accordingly Figure 2 are shown; Figure 12 Details of the distortion curve of the camera system's recording unit for the in Figure 11 The embodiment shown is shown; Figure 13a schematic top view of a commercial vehicle, which schematically shows the movement of an area to be depicted depending on the driving conditions of the vehicle; and Figure 14 a schematic view of an image sensor area of ​​the recording unit of the camera system, which shows the displacement of the areas of interest according to Figure 13 illustrated on the image sensor surface. DESCRIPTION OF PREFERRED EXECUTION FORMS

[0055] In Figure 1A schematic diagram shows a mirror replacement system 100 for, for example, a commercial vehicle. The mirror replacement system 100 can be integrated into a driver assistance system or used as a standalone mirror replacement system 100. The mirror replacement system 100 comprises a camera system 130, a processing unit 120, and a display unit 110. Image data captured by the camera system 130 is fed to the processing unit 120, which, after appropriate processing, then feeds this image data to a display unit 110 in a format visible to the driver of the vehicle. The mirror replacement system 100 can also be coupled with one or more vehicle sensors 140, which also supply data to the processing unit 120, such as the current driving status (steering angle, speed, direction of travel) of the vehicle. The processing unit 120 takes this data into account when processing the data received from the camera system 130.Alternatively, the vehicle sensor(s) 140 could also be directly coupled to the camera system 130, so that the latter is controlled directly based on the data received by the vehicle sensor(s) 140. Similarly, it is also possible for the processing unit 120 to output data to the camera system 130 for controlling the camera system 130.

[0056] The processing unit 120 can be provided as a separate processing unit from the camera system 130, for example in the form of the vehicle's on-board computer, or it can alternatively be integrated into the camera system 130. The display unit 110 is, for example, a monitor mounted in the vehicle on which the data provided by the processing unit 120 is displayed for the driver to see. Alternatively, instead of a monitor in the vehicle, a display device located outside the vehicle, for example in the area of ​​conventional vehicle mirrors, could also be provided. Furthermore, the display unit could be implemented as a projection onto a vehicle structural component in the vehicle's interior.With regard to the playback unit 110, it should also be noted that, in addition to the illustrated embodiment in which a monitor is used to display the data provided by the processing unit 120, the playback unit can also consist of several separate monitors or display devices. These can be identical or different from each other, as required.

[0057] Furthermore, the mirror replacement system 100, especially when used as part of an Advanced Driver Assistance System (ADAS), and in particular its processing unit 120, is connected as required to other information or control components of the vehicle 150, which in turn may be display devices for the driver, for example audio display devices, or components that directly control the vehicle, such as steering aids.

[0058] The camera system 130 contains at least one recording unit 30, which is described in more detail below, but can also contain several recording units 30 of the described type. Furthermore, additional recording units 31 may be provided, which do not necessarily have to meet the requirements placed on the recording units 30. Accordingly, it is possible that the processing unit, as in Figure 1 As indicated, the processing unit 120 receives image data directly from the individual recording units 30 and 31, instead of receiving it from the general camera system 130. Accordingly, the processing unit 120 can also send control signals directly to the individual recording units 30 and 31.

[0059] Figure 2 shows in perspective view a commercial vehicle 10 equipped with a mirror replacement system 100 according to Figure 1 is equipped. Accordingly, one or more receiving units 30 are attached to the commercial vehicle 10. As in Figure 2 As shown, the exemplary mirror replacement system 100, which is attached to the commercial vehicle 10, is designed to capture a field of view 11 of a main mirror and a field of view 12 of a wide-angle mirror by means of the recording unit 30 and to display it in or on the driver's cab of the commercial vehicle 10 so that it is visible to the driver. Figure 2 The field of view 11 of a main mirror and the field of view 12 of a wide-angle mirror are schematically shown with dashed lines (field of view 11 of a main mirror with long dashed lines, field of view 12 of a wide-angle mirror with shorter dashed lines) on the flat road surface next to the vehicle 10.

[0060] In Figure 2 Furthermore, the forward direction of travel is indicated by an arrow D. All directional references in this description, i.e., front, rear, left, right, etc., refer to this forward direction of travel D of the vehicle.

[0061] The in Figure 2 The depicted field of view 1 of the main mirror extends laterally away from the vehicle and rearward from a side boundary line 13 of the vehicle. The side boundary line 13 is a line defined by the intersection of the flat, horizontal roadway with a plane parallel to the longitudinal median plane (not shown) of the vehicle, which passes through the outermost point of the vehicle in the lateral direction.

[0062] The optical axis 302 of the optical element 301 ( Figures 3, 4The optical axis 30 of the recording unit, which is provided, for example, by a camera, extends laterally at an angle to the vehicle's longitudinal median plane and to the road surface such that it intersects the field of view 11 of a primary mirror on the road surface. This means that the intersection point S of the optical axis 302 with the road surface is located within the field of view 11 of a primary mirror when the optical axis 302 is located within the field of view 11 of the primary mirror. Figure 2 The illustrated embodiment is located. Preferably, this intersection point S is located a maximum of 6 m behind the receiving unit 30 when viewed in the longitudinal direction of the vehicle, and more preferably in the range of 4 to 5 m.

[0063] In Figure 2Furthermore, a sight line 14 is drawn with thin dotted lines, which is determined by that section of a line that is perpendicular to the side boundary line 13 and passes through the intersection point S of the optical axis 302 with the road surface, which lies within the area of ​​the field of view 11 of the main mirror.

[0064] The recording unit 31 of the camera system 130 will be described in more detail below with reference to Figures 3 and 4 , which schematically show the passage of rays through a schematically represented optical element in sectional view or in perspective view (cut), as well as based on Figures 5 and 6 , which schematically illustrate the embodiments for a structure of the optical element.

[0065] The optical element 301, together with an image sensor 302, forms the essential components of the recording unit 30 of the camera system for a motor vehicle. The optical element 301 is, as shown in Figures 3 and 4As can be seen, in the present embodiment, the image sensor is essentially rotationally symmetric about the optical axis 302. This means that every light ray incident on the image sensor 30 from a point on the object to be imaged at the same angle, for example α1, to the optical axis 302, is imaged on the image sensor surface 304 with the same distortion and rotational symmetric about the optical axis. The angle α, which is also referred to below as the object angle α, corresponds to the angle of incidence of the light ray into an optical element 301 with an incident surface perpendicular to the optical axis 302 (not shown virtually). Accordingly, every light ray incident at the object angle α1 is imaged on the image sensor surface 304 at a distance r1 from the optical axis 302.The image sensor area 304 is the area that is actually available for imaging within the entire image opening angle of the optical element 301, i.e., the area of ​​the image sensor 302 that is suitable for imaging and faces the optical element 301.

[0066] In Figures 3 and 4The beam paths through the optical element 301 and their imaging onto the image sensor surface 304 of the image sensor 303 at distances r1, r2, ..., rn are shown schematically for various object angles α1, α2, ..., rn. Since the optical element 301 is rotationally symmetric in the illustrated embodiment, the distance r1, r2, ..., rn and the beam path through the optical element 301 are also rotationally symmetric with respect to the optical axis 302. The optical axis 302, for which α = α0 = 0°, r = r0 = 0, intersects the image sensor surface 304 at the origin of a distortion curve (α = 0; r = 0) of an α,r coordinate system.

[0067] The optical element 301, which, as in Figures 5 and 6The optical element, which is schematically represented and consists of a lens system and possibly other optical components containing several rotationally symmetric lenses arranged in series, has a so-called distortion curve r = f(α), which is a geometric aberration of the optical element that leads to a local change in the image scale. Due to the rotational symmetry of the optical element 301, in the Figures 3 and 4 In the embodiment shown, the distortion curve r = f(α) is also rotationally symmetric to the optical axis 302.

[0068] One embodiment of the lens arrangement is shown in Figure 5 shown. The seven lenses 314 to 320 are arranged in a row along the path of the incident light (from left to right in Figure 5) arranged. Lens 314 is a spherical convex-concave lens, lens 315 is a spherical convex-concave lens. Lens 316 is formed by a spherical concave-convex lens, lens 317 by a lens with a freeform surface (aspheric lens) having a convex-concave and a concave surface, lens 318 is a spherical biconvex lens, lens 319 is an aspheric lens with a convex and a convex-concave surface, and lens 320 is an aspheric lens with a concave and a convex-concave surface. The freeform surfaces of lenses 317 and 320 are also rotationally symmetric, so that the optical element 301 of the embodiment, formed by the seven lenses, is Figure 5 is rotationally symmetrical about the optical axis 302. In the embodiment, in front of the image sensor 303, Figure 6 Likewise, a sensor protection glass 305 and an infrared filter 329 are provided (see embodiment in Figure 6 Here too, the optical element 301 exhibits the schematically indicated ray path, as well as a distortion curve r = f(α) with an inflection point in the range 0 < r < r max .

[0069] At the in Figure 6 In the alternative embodiment of the optical element 301 shown, the optical element 301 contains eight in a row along the beam path of the incident light (from left to right in Figure 6) arranged lenses 306, 307, 308, 309, 310, 311, 312, 313. In the order in which the incident light passes through the lenses on its way to the image sensor 303, lens 306 is a spherical convex-concave lens, lens 307 is a spherical convex-concave lens, lens 308 is a spherical concave-convex lens, lenses 309 and 310 are each a spherical bi-convex lens, lens 311 is a spherical bi-concave lens, lens 312 is a freeform lens (aspherical lens) with a rotationally symmetric convex-concave and a convex surface, and lens 313 is an aspherical concave-spherical convex lens. Furthermore, a sensor protection glass 305 is mounted in front of the image sensor 303, as is an infrared filter 329 as supplementary optical components. By means of such a lens arrangement, the incident light is focused, as is the case for some rays in Fig. 6As an example, the optical element 301 guides and deflects the light. Due to this and the corresponding lens arrangement, the optical element 301 as a whole exhibits the distortion curve r = f(α), which has an inflection point in the region of the image sensor area 304 0 < r < r max.

[0070] Both the in Fig. 5 shown as well as the one in Fig. 6 The optical system shown includes an aperture 303 as an additional component. Further filters, apertures, etc., can be provided as needed. The lenses can be made of glass (primarily spherical lenses) or plastic, for example. Different materials can be combined as required. The lenses can also be coated with, for example, vapor-deposited metallic or other coatings, which generally do not affect the light calculation but serve to influence scattering, eliminate unwanted reflections, etc.

[0071] Most of the lenses 307 to 320 of the in Figures 5 and 6 The embodiments shown are lenses with at least one semi-spherical surface. For example, lens 312, lens 317, and lens 320 are so-called aspherical lenses, which have at least one surface that is not semi-spherical. Furthermore, even though it is in Figures 5 and 6 Not shown, it is also possible to make the optical element 301 anamorphic by selecting suitable lenses that are not rotationally symmetric to the optical axis 302, so that the optical element has a distortion curve that is not rotationally symmetric to the optical axis.

[0072] With the in Figures 5 and 6In the illustrated lens arrangements, which are exemplary, rotationally symmetric distortion curves r = f(α) of the optical element can be generated. These curves are functions r = f(α) that have an inflection point (αw; rw) within the maximum distance rmax, which is the maximum distance of a point on the image sensor surface 304 to the optical axis 302 on the image sensor surface 304. For the distortion curve r = f(α) to have the inflection point within 0 < r(α) < rmax, the following must hold for an αw corresponding to a radius rw on the image sensor surface 304 that is smaller than rmax (rw < rmax): r'' = f''(α w ) = d 2< r / dα 2< (α = α w ) = 0; r'' = f''(α) < 0 for 0 < α < α w ; r'" = f"(α) > 0 for α w < α < α max . Such a distortion curve, which is caused, for example, by the lens arrangements of the optical element according to Figures 5 and 6 which can be generated is schematically in Figure 7 shown. Its first derivative is in Figure 8shown and its second derivative is shown in Figure 9.

[0073] As in Figure 7 As shown in an α,r-coordinate system, an inflection point (αw; rw) exists in the region [0; rmax]. For a specific object angle α = α2 = αw, the second derivative ( Figure 9 ) the distortion curve is zero, that is, it has a zero crossing at α w. Before the inflection point, that is, in the region 0° < α < α w, as in Figure 9 It is evident that the second derivative of the distortion curve r = f(α) is negative; for the range αw < αmax, the distortion curve is positive. This means that, as in Figure 7 It can be seen that the distortion curve r(α) is right-curved in a first range of 0° < α < α w and is left-curved in a second range of α w < α < α max.

[0074] The origin of the α,r coordinate system in Figure 7, that is, r = 0 mm, α = 0°, corresponds to the point on the optical axis 302 on the image sensor. r max is the maximum distance a point on the image sensor can have from the optical axis 302. If the optical axis is centered in a rectangular image sensor, that is, located at the centroid of the area, where the rectangular image sensor has edge lengths a, b, then the following applies: r max = a 2 + b 2 If the optical axis is not arranged centrally on the image sensor, then the distance r max is the distance between the optical axis 302 on the image sensor surface 304 and the furthest corner of the image sensor surface 304.

[0075] Figures 10a and 10b The distortion curve r = f(α) for an optical element 301 of the recording unit 30 is shown, also in the α,r coordinate system, in comparison to various prior art distortion curves. This shows Figure 10bAn enlarged section Z in the region of the origin of the α,r coordinate system. The distortion curve r = f(α), which has an inflection point (αw; rw) in the region 0 < α < αmax, is shown with a solid line and labeled f1. f2 denotes a gnomonic distortion curve (distortion-free), f3 a stereographic distortion curve (i.e., a conformal distortion curve), f4 an equidistant distortion curve, f5 an equal-area distortion curve, and f6 an orthographic distortion curve. The focal lengths with respect to the distortion curves are chosen such that all distortion curves pass through the point (αw; rw).

[0076] As from Figure 10a and Figure 10bAs can be seen, the distortion curve f1 has an inflection point at the point (αw; rw) where the curvature of the distortion curve changes from concave down (in the range 0 < α < αw) to concave up (in the range αw < α < αmax). Furthermore, as is particularly evident... Figure 10bAs can be seen, the slope of the distortion curve f1 in the region near the origin of the α,r coordinate system is large, especially compared to the other distortion curves. This means that a relatively large area is provided for imaging a relatively small angle on the image sensor 303, which in turn allows this region to be imaged with high resolution. Furthermore, the slope of the distortion curve r = f1(α) is minimal at the inflection point (αw; rw), meaning that the slope is relatively small at the inflection point itself and in its immediate vicinity. Finally, for αmax, the slope of the distortion curve is preferably again maximal or relatively large, as can be seen in particular in the figure in Figure 10a can be seen.

[0077] Such a distortion curve, as seen in Figures 7 to 10b As explained, for example, a polynomial function f α = ∑ i = 0 n α i α i described. Alternatively, a spline function can describe the distortion curve, which is a domain-wise polynomial function, that is, a function composed of several polynomial pieces, or a Bézier curve, which is a mathematically formulated curve (numerically generated curve).

[0078] With reference to Figure 11 and Figure 12 A diagram of the fields of vision 11, 12 for the commercial vehicle 10 ( Figure 2 ), which are recorded using the camera system 130, on the image sensor area 304. The image sensor area 304 of the image sensor 303, which is in Figure 11 The figure shown is rectangular with side lengths a and b of the rectangle. As shown in Figure 11As can be seen, in the illustrated embodiment the optical axis 302 is arranged eccentrically with respect to the image sensor surface 304, that is, outside the centroid of the image sensor surface 304. In particular, the optical axis 302 is off-center with respect to side a of the rectangular image sensor surface 304. This results in a maximum distance f 3 = r max from the optical axis 302 on the image sensor surface 304 to the furthest corners of the image sensor surface 304. Furthermore, in accordance with Figures 10a and 10bThe radii centered on the optical axis 302 are shown, which pass through the inflection point of the distortion curve r = f(α) (r 2 = rw ), a radius r SB corresponding to the maximum distance from the optical axis 302 to the sensor surface edge parallel to the sideline a; a radius r SH corresponding to the maximum distance from the optical axis 302 on the sensor surface 304 to the sensor surface edge parallel to the sensor edge b; and a radius r 1 which corresponds to a Figures 10a and 10b The first radius r1 shown corresponds to an angle α1. Figure 11 Furthermore, Figure 11' shows the field of view 11 of the main mirror (see Figure 2 ) as well as Figure 12' of the field of view 12 of the wide-angle mirror (see Figure 2) is entered, as is an image 15' of the horizon line. As can be seen, the image 11' of the field of view 11 of the primary mirror lies largely within a region that is within the radius r 1, so that this region within the radius r 1 is imaged with increased resolution compared to standard distortion curves of the prior art. Furthermore, the entire image 12' of the field of view 12 of the wide-angle mirror can be produced on the same image sensor with the same optical element. It is not necessary to provide a second optical element and / or a second image sensor and, for display purposes, to subsequently combine the images.

[0079] In Figure 11 Furthermore, Figure 14' of the line of sight 14 (see Figure 2 ) entered. As from Figure 11 As can be seen, this runs essentially parallel to a side edge of the image sensor area 304 (the side edge a).

[0080] In Figure 12This image 14' of the line of sight is also plotted in the α,r coordinate system in addition to the image of the distortion curve r = f 1 (α). It is clearly evident that the entire width of the image of the field of view 11 of the primary mirror lies within the region of 0 < α < α w that is in the right-curved region of the distortion curve r = f(α) and thus provides high resolution (especially compared to the distortion curves of conventional optical systems).

[0081] In the present described embodiment, in which the camera system 130 is used for a mirror replacement system 100 of a vehicle, a processing unit 120 of the mirror replacement system 100 can subsequently evaluate the image data recorded on the image sensor 303 and display it for a driver, who is, for example, sitting in the cab of a commercial vehicle, to see, for example, on a monitor. In the present embodiment, separate areas for the field of view 11 of a main mirror and the field of view 12 of a wide-angle mirror are read out and, according to a preferred embodiment (not shown), are also displayed to the driver on separate areas of the display unit 110. The separate areas can, for example, be provided on a common monitor or on separate monitors.Thus, it is possible to model the familiar appearance of a main and a wide-angle mirror for the driver of the commercial vehicle. If the camera system 130 is used, for example, as part of a driver assistance system, the relevant areas of the image sensor surface 304 can also be evaluated by a processing unit 120 with regard to specific environmental information (e.g., lane markings, traffic signs, other road users, etc.) and, depending on the information captured and determined, the vehicle control can be intervened, instructions or information can be displayed to the driver, or similar actions can be taken.

[0082] In a mirror replacement system 100, as previously described, it is also possible, depending on the driving situation of a vehicle, for example a commercial vehicle 10, to extract data from different areas of the image sensor surface 304 for display on the playback unit 110 for the driver, i.e., to evaluate different areas of the image sensor surface 304 at different times during driving. This is illustrated by reference to Figures 13 and 14 explained.

[0083] This shows Figure 13 A top view of a commercial vehicle traveling forward or straight ahead, with the field of view 11 of a main mirror and the field of view 12 of a wide-angle mirror schematically shown. Figure 14Figure 304 also shows, for the case of straight-ahead driving, the image sensor area 304 with image 11' of the field of view 11 and image 12' of the field of view 12. During normal straight-ahead driving, as previously explained, area 21' is extracted from the data in a specific, first area on the image sensor area 304 to display the field of view 11 of the main mirror, or to allow the driver to see into the field of view 11 of the main mirror. If the driving situation changes, the area of ​​interest may shift from the originally relevant area 21 to the shifted area 22, provided the recording unit 30 on the vehicle remains aligned. This can occur, for example, when a commercial vehicle, especially one with a trailer, is cornering or maneuvering. In this case, the area of ​​interest, which corresponds to the field of view 11 of the main mirror, shifts, as shown in Figure 200. Figure 13as shown, into area 22. Using the camera system 130 with the recording unit 30 with the optical element 301, which has the distortion curve r = f(α) of the described type, it is also possible to shift the area on the image sensor surface 304 from which image sensor data are extracted, so that, as shown in Figure 14As shown, image data of an area 22' on the image sensor surface 304 is extracted. This is possible without losing the required accuracy of the image data, i.e., in particular the resolution, since the distortion curve r = f(α) can provide the required resolution and distortion in all areas from which data can potentially be extracted, without data post-processing. Thus, the field of view 11, or its image 11', can be adjusted according to the driving situation. No mechanical adjustment of the recording unit 30 is required for this. Rather, this can be achieved solely by extracting the image data from the image sensor 304 in selected areas.

[0084] These advantages are achieved by using at least one recording unit 30 which has an optical element 301 with a distortion curve r = f(α) which has an inflection point on the image sensor surface 304 within the maximum distance of a point of the image sensor surface 304 to the optical axis 302.

[0085] It is explicitly emphasized that all features disclosed in the description and / or the claims are to be considered separate and independent of one another for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, irrespective of the combinations of features in the embodiments and / or the claims. The invention is defined in the claims. Reference symbol list

[0086] 10 Commercial vehicle 11 Field of view of a primary mirror 12 Field of view of a wide-angle mirror 13 Side boundary line 14 Viewing distance 11' Image of the field of view 11 12' Image of the field of view 12 14' Image of the viewing distance 14 15' Image of the horizon line 21' Extracted area 22' Extracted area 30 Camera unit 31 Camera unit 301 Optical element 302 Optical axis 303 Image sensor 304 Image sensor area 305 Sensor protective glass 306 Lens 307 Lens 308 Lens 309 Lens 310 Lens 311 Lens 312 Lens 313 Lens 314 Lens 315 Lens 316 Lens 317 Lens 318 Lens 319 Lens 320Lens 329IR filter 330Aperture 100Mirror replacement system 110Playback unit 120Processing unit 130Camera system 140Vehicle sensor 150Control unit fDistortion curve f1 Distortion curve f2 Distortion curve (distortion-free, gnomonic) f3 Distortion curve (angle-preserving, stereographic) f4 Distortion curve (equidistant) f5 Distortion curve (area-preserving,(orthographic) f 6 Distortion curve (orthographic) f βi Distortion curve aSide edge of the image sensor area bSide edge of the image sensor area DForward direction of travel of the vehicle SIntersection point αObject angle of the incident light βRotation angle about the optical axis rDistance from a point on the image sensor area to the optical axis,

Claims

1. A mirror replacement system, wherein the mirror replacement system is part of a commercial vehicle (10), comprising one or more camera systems (130), wherein the camera system (130) comprises: a capture unit (30), which comprises an optical element (301) and an image sensor (303) with an image sensor surface (304), wherein the optical element (301) has a distortion with a distortion curve r = f(α), wherein r is the distance of an object point depicted on the image sensor surface (304) to the intersection point of the optical axis (302) with the image sensor surface (304), and α is the angle between the optical axis (302) of the optical element (301) and the beam incident in the optical element (301) from the object point, the distortion curve r = f(α) for rw = f (αw) has an inflection point (αw; rw) within 0 < r < rmax, for which r" = f"(αw) = d2r / dα2(αw) = 0 applies, wherein rmax is the distance r = f(αmax) on the image sensor surface (304) from the optical axis (302) to the most distant boundary point of the image sensor surface (304), and for the curvature if the distortion curve r " = f " α < 0 for 0 ° < α < α w r " = f " α > 0 for α w < α < α max applies , and a processing unit (120) to process the data of the capture unit (30) and / or a reproduction unit (110) for the reproduction of information captured using the capture unit perceptible to the driver of the vehicle, wherein the capture unit (30) is adapted to capture both the field of vision (11) of a main mirror according to ECE-R46, as well as the field of vision (12) of a wide-angle mirror according to ECE-R46 of the same side of the commercial vehicle (10), wherein the optical axis (302) of the optical element (301) of the capture unit (30) intersects the field of vision (11; 12) or one of the fields of view (11; 12), and wherein the optical axis (302) of the optical element (301) crosses one of the fields of view (11; 12) in an intersection point (S) at a maximum distance of 5m to a lateral boundary line (13) of the vehicle, wherein the lateral boundary line (13) is an intersecting line of a plane parallel to the central longitudinal plane of the vehicle, which passes through a lateral outermost point of the vehicle (10), with the horizontal, plane road.

2. The mirror replacement system (130) according to claim 1, wherein the distortion curve r = f(α) has exactly one inflection point (αw; rw) within 0 < r < rmax.

3. The mirror replacement system (130) according to claim 1 or 2, wherein the gradient r' = dr / dα of the distortion curve r = f(α) is maximal within the range 0° < α < αw at the zero point r = f(0) = 0 of the distortion curve, or wherein the gradient r' = dr / dα of the distortion curve r = f(α) is maximal within the range αw < α < αmax for αmax (r = f(αmax) = rmax) of the distortion curve and / or wherein the gradient r' = dr / dα of the distortion curve r = f(α) is minimal at the inflection point r = f(αw) = rw of the distortion curve.

4. The mirror replacement system (130) according to any of the preceding claims, wherein the distortion curve r = f(α) is one of either a polynomial function f α = ∑ i = 0 n α i α i , a spline function, or a Bézier curve.

5. The mirror replacement system (130) according to any of the preceding claims, wherein the centroid of the image sensor surface (304) and the intersection point of the optical axis (302) with the image sensor surface (304) do not coincide, wherein in particular the optical axis (302) is disposed eccentrically with respect to the image sensor surface (304).

6. The mirror replacement system (130) according to any of the preceding claims, wherein the optical element (301) comprises one or more aspherical lenses, and / or wherein the optical element (301) comprises two or more lenses that are different from each other.

7. The mirror replacement system (130) according to any of the preceding claims, wherein the optical element (301) has a rotationally symmetric distortion with regard to its optical axis (302), such that the distortion curves r = f(α) are identical for every angle of rotation β around the optical axis (302).

8. The mirror replacement system (130) according any of the claims 1 to 6, wherein the optical element (301) has a distortion that is not rotationally symmetric with regard to its optical axis (302), such that a first distortion curve r1 = f(α) for an angle of rotation β1 around the optical axis, differs from a second distortion curve r2 = f(α) for an angle of rotation β2 around the optical axis.

9. The mirror replacement system (130) according to claim 8, wherein the optical element (301) is anamorphic.

10. The mirror replacement system according to any of the preceding claims, wherein the mirror replacement system is adapted to display two of more fields of view surrounding the vehicle such that they are visible to the driver of the vehicle, wherein preferably a first field of vision is visible in a first region of the reproduction unit and a second field of vision is visible in a second, optically separated region of the reproduction unit, wherein especially the mirror replacement system is adapted to capture the field of vision information of the two fields of view (11, 12) by means of a joint / common capture unit (30) of the camera system (130), and the processing unit (120) is adapted to separate and extract the data received from the capture unit (30) into information to be displayed in the first region of the reproduction unit and in the second region of the reproduction unit, respectively.

11. The mirror replacement system according to claim 10, wherein the processing unit (120) is adapted to, depending on a driving direction of the vehicle captured, and transmitted to the processing unit (120) by a sensor, adjust the information extracted from the data captured by the capture unit for the first and / or second section in terms of to their position in the image captured by the capture unit (30).

12. The mirror replacement system according to any of the preceding claims, wherein the mirror replacement system is adapted to visually display the information captured by the capture unit (30), and is further adapted to display one or more fields of view lying on a plane, horizontal part of the road surrounding the vehicle, on the reproduction unit (110) such that it is visible to the driver of the vehicle.

13. The mirror replacement system according to any of the preceding claims, wherein a line of sight (14) perpendicular to the lateral boundary line (13), and that passes through the intersection point (S), and is limited by the limits of the field of vision of the main mirror, is in the range of the distortion curve r = f(α) for 0° < α < αw with r" = f‴(α) < 0, wherein preferably, the inflection point (αw; rw) is beyond the of the line of sight (14).

14. A driver assistance system comprising a mirror replacement system according to any of the preceding claims.